The opened seam about 0.5 m below the deck level forward, the non-continuous welding between the deck and the side shell plating, the perforated main deck plating and the open-topped stand pipes allowed water easy ingress to the interior of the barge. This flooding problem had existed for some time; the portable pump had been placed aboard to cope with it. Because the barge was proceeding through choppy water and at a higher speed than usual, it is likely that the bow wave water rose further up the hull than it normally did. Additionally, the higher speed would have accelerated the rate at which the barge took on water. Although the tugmaster recognized that the barge was settling in the water some 30 minutes before it sank, he did not start the bilge pump to counter the ingress of water. It is likely that he did not appreciate the rate at which the barge was flooding. Had he started the pump at this time, the sinking may have been prevented. The practical examination for the tugmaster's certificate did not require an in-depth understanding of vessel stability in general or of the effect of free-surface liquids on stability in particular. The tugmaster's decision to move the trucks across the deck to counter the list indicates that he did not consider that the list may have resulted from anything other than an unequal distribution of weight. The initial list to starboard was most likely due to the accumulation of floodwater which entered the hull through the damaged and partially welded shell plating seams on that side. The free-surface effect and weight of this floodwater would have markedly reduced the barge's transverse stability and effective freeboard. Consequently, the decision to move the vehicles across the deck, the inertial effects caused by the course alteration to starboard and the sudden upthrust due to the barge grounding on its starboard side caused the floodwater to surge to port and induce a greater list on that side. Subsequent downflooding through the immersed open-topped stand pipes near the main deck edge further increased the port list and caused the unsecured vehicles to self-discharge. The downflooding continued until reserve buoyancy was lost and the barge sank. Because the system of making the tug fast to the barge did not incorporate a quick-release mechanism, the tugmaster had difficulty disconnecting the chains while the barge was heeling and sinking. It was fortunate that he succeeded in doing so as the tug was also in danger of being hove under and of sinking with the barge. It is not known if the chains would have broken had the tugmaster been unsuccessful in letting them go. Because the barge does not carry passengers and has no crew on board, there is no regulatory requirement for safety or life-saving equipment to be carried on board the barge. However, when persons such as the truck drivers are required to work or to travel on board, the responsibility to provide safety or life-saving equipment rests with the person requiring them to do so. There was no such equipment on board.Analysis The opened seam about 0.5 m below the deck level forward, the non-continuous welding between the deck and the side shell plating, the perforated main deck plating and the open-topped stand pipes allowed water easy ingress to the interior of the barge. This flooding problem had existed for some time; the portable pump had been placed aboard to cope with it. Because the barge was proceeding through choppy water and at a higher speed than usual, it is likely that the bow wave water rose further up the hull than it normally did. Additionally, the higher speed would have accelerated the rate at which the barge took on water. Although the tugmaster recognized that the barge was settling in the water some 30 minutes before it sank, he did not start the bilge pump to counter the ingress of water. It is likely that he did not appreciate the rate at which the barge was flooding. Had he started the pump at this time, the sinking may have been prevented. The practical examination for the tugmaster's certificate did not require an in-depth understanding of vessel stability in general or of the effect of free-surface liquids on stability in particular. The tugmaster's decision to move the trucks across the deck to counter the list indicates that he did not consider that the list may have resulted from anything other than an unequal distribution of weight. The initial list to starboard was most likely due to the accumulation of floodwater which entered the hull through the damaged and partially welded shell plating seams on that side. The free-surface effect and weight of this floodwater would have markedly reduced the barge's transverse stability and effective freeboard. Consequently, the decision to move the vehicles across the deck, the inertial effects caused by the course alteration to starboard and the sudden upthrust due to the barge grounding on its starboard side caused the floodwater to surge to port and induce a greater list on that side. Subsequent downflooding through the immersed open-topped stand pipes near the main deck edge further increased the port list and caused the unsecured vehicles to self-discharge. The downflooding continued until reserve buoyancy was lost and the barge sank. Because the system of making the tug fast to the barge did not incorporate a quick-release mechanism, the tugmaster had difficulty disconnecting the chains while the barge was heeling and sinking. It was fortunate that he succeeded in doing so as the tug was also in danger of being hove under and of sinking with the barge. It is not known if the chains would have broken had the tugmaster been unsuccessful in letting them go. Because the barge does not carry passengers and has no crew on board, there is no regulatory requirement for safety or life-saving equipment to be carried on board the barge. However, when persons such as the truck drivers are required to work or to travel on board, the responsibility to provide safety or life-saving equipment rests with the person requiring them to do so. There was no such equipment on board. The barge does not carry passengers, has no crew on board and is not subject to inspection by Transport Canada Marine Safety. Life-saving appliances were not provided on the barge for the use of the truck drivers who were working and travelling on board. Before the converted barge entered service, its owner did not have a competent person determine the barge's maximum deck load, freeboard or trim and stability characteristics. The owner did not provide barge operators with formal guidance or instructions regarding the safe loading, trim or stability limitations of the barge. The barge was highly vulnerable to downflooding through the open-topped stand pipes on the main deck. The watertight integrity of the barge's hull was compromised due to non-continuous structural welding, unrepaired shell plating damage and corrosion-related perforations in the main deck plating. During the passage, water ingressed through the unrepaired shell plating damage and non-continuous structural welding. The tugmaster did not start the portable bilge pump to pump out the water in the barge when he first noticed that the barge's freeboard was decreasing. The lack of adequate subdivision in the barge augmented the free-surface effect of the floodwater and markedly reduced the barge's transverse stability. The effect of moving the trucks to port to counter the starboard list, combined with the inertial effects of the turn to starboard, caused the water in the barge to surge to port and induce a greater angle of heel on that side. The upthrust from the grounding effect increased the rate at which the port list developed, accelerated the ingress of water and the self-discharge of the trucks from the deck. The increased rate in the ingress of water due to the deeper immersion of the hull and the onset of downflooding through the open-topped deck stand pipes, exceeded the capacity of the portable bilge pump. Downflooding continued until reserve buoyancy was lost and the barge sank. The trucks on deck were neither chocked nor secured, nor were securing points or devices provided.Findings The barge does not carry passengers, has no crew on board and is not subject to inspection by Transport Canada Marine Safety. Life-saving appliances were not provided on the barge for the use of the truck drivers who were working and travelling on board. Before the converted barge entered service, its owner did not have a competent person determine the barge's maximum deck load, freeboard or trim and stability characteristics. The owner did not provide barge operators with formal guidance or instructions regarding the safe loading, trim or stability limitations of the barge. The barge was highly vulnerable to downflooding through the open-topped stand pipes on the main deck. The watertight integrity of the barge's hull was compromised due to non-continuous structural welding, unrepaired shell plating damage and corrosion-related perforations in the main deck plating. During the passage, water ingressed through the unrepaired shell plating damage and non-continuous structural welding. The tugmaster did not start the portable bilge pump to pump out the water in the barge when he first noticed that the barge's freeboard was decreasing. The lack of adequate subdivision in the barge augmented the free-surface effect of the floodwater and markedly reduced the barge's transverse stability. The effect of moving the trucks to port to counter the starboard list, combined with the inertial effects of the turn to starboard, caused the water in the barge to surge to port and induce a greater angle of heel on that side. The upthrust from the grounding effect increased the rate at which the port list developed, accelerated the ingress of water and the self-discharge of the trucks from the deck. The increased rate in the ingress of water due to the deeper immersion of the hull and the onset of downflooding through the open-topped deck stand pipes, exceeded the capacity of the portable bilge pump. Downflooding continued until reserve buoyancy was lost and the barge sank. The trucks on deck were neither chocked nor secured, nor were securing points or devices provided. Floodwater, which entered the hull through the damaged and partially welded seams and was not pumped out, accumulated inside the barge and induced a slight list to starboard. The resulting free-surface effect markedly reduced the barge's transverse stability to the extent that a greater list to port was caused after the trucks carried on deck were moved toward that side. After the barge grounded on an underwater rock on its starboard side, the port list increased, downflooding occurred through openings in the main deck which increased the port list and caused the trucks to slide to port and self-discharge over the side. The downflooding continued until reserve buoyancy was lost and the barge sank. Contributing to the sinking was the fact that the tugmaster did not have an in-depth understanding of vessel stability in general or of the effect of free-surface liquids on stability in particular.Causes and Contributing Factors Floodwater, which entered the hull through the damaged and partially welded seams and was not pumped out, accumulated inside the barge and induced a slight list to starboard. The resulting free-surface effect markedly reduced the barge's transverse stability to the extent that a greater list to port was caused after the trucks carried on deck were moved toward that side. After the barge grounded on an underwater rock on its starboard side, the port list increased, downflooding occurred through openings in the main deck which increased the port list and caused the trucks to slide to port and self-discharge over the side. The downflooding continued until reserve buoyancy was lost and the barge sank. Contributing to the sinking was the fact that the tugmaster did not have an in-depth understanding of vessel stability in general or of the effect of free-surface liquids on stability in particular. After the barge was salvaged, TC Marine Safety, Collingwood, issued a written notice to the owner requiring that repairs be carried out to make the barge watertight and seaworthy before it could re-enter service. The repairs were completed to the satisfaction of TC Marine Safety on 27 September 1996.Safety Action Taken After the barge was salvaged, TC Marine Safety, Collingwood, issued a written notice to the owner requiring that repairs be carried out to make the barge watertight and seaworthy before it could re-enter service. The repairs were completed to the satisfaction of TC Marine Safety on 27 September 1996.